1. Field of the Invention
The present invention relates to a projector, and more particularly to a projector capable of reducing speckle interference.
2. Description of the Related Art
Conventionally, when laser sources are utilized as light sources of projectors, high-coherence in laser beams tends to bring speckle interference, which blurs projection image or decreases image quality. Consequently, an additional diffuser is thus required to reduce coherence of laser beams.
U.S. Pat. Nos. 5,313,479, 6,594,090, 6,874,893 and 6,005,722 teach that additional diffusers are disposed on light paths to reduce coherence in laser beams. These diffusers, however, increase the number of optical elements, enlarge volume of the optical-mechanical systems, and raise design difficulties and costs thereof.